The Sigma 30mm ƒ/1.4 DC Art is yet another lens to undergo Sigma's Global Vision makeover. An updated version of the popular Sigma 30mm ƒ/1.4 EX DC HSM, the new version gets an "Art" Series designation, along with updated construction using Sigma's Thermally Stable Composite Material, new optical layout and compatibility with Sigma's USB Dock configuration and adjustment system.

As expected, the Sigma 30mm ƒ/1.4 DC Art comes in a variety of flavors for APS-C cameras including Canon, Nikon and Sigma camera mounts. The previous model also came in Sony Alpha and Pentax mounts, but these are currently not available for the new version.

The new Sigma 30mm prime lens takes 62mm filters like its predecessor does, and weighs just slightly more. And like most Sigma lenses, this one is available for a nice, budget-friendly price of around $499 and ships with front and rear caps, a lens hood and a soft case.

Sharpness
Overall, the Sigma 30mm ƒ/1.4 DC Art produces very sharp images. Wide open at ƒ/1.4, images are a little soft except for in the dead center of the frame, however, when compared to its predecessor, the new Art-Series model shows vastly improved performance at max aperture. Stopping down to ƒ/2.8 shows a significant increase in sharpness, and it stays very sharp throughout the aperture range with only minor diffraction softness at ƒ/16.

Chromatic Aberration
Chromatic aberration is not really a significant issue with this lens, and it looks fairly similar to the older model in this regard, if only slightly worse. At ƒ/1.4, both models averaged around 300ths of a percent of frame height, and while the older model averaged around a more or less constant value, the new version shows an increase in CA as you stop down to just around 600ths of a percent at ƒ/16.

Shading (''Vignetting'')
Unlike CA, vignetting has been much improved in this new model compared to the older one. While both models displayed about half of a stop of light falloff wide open, the new model shows a sharp decrease to nearly zero light loss by ƒ/2.8, and remains at that level throughout the rest of the aperture values. The older model, on the other hand, showed a slow, steady decrease in CA, but even by ƒ/8, the older version had more vignetting than the new one does at ƒ/2.8.

Distortion
The Sigma 30mm ƒ/1.4 DC Art has a moderate amount of barrel distortion at 0.5% at the corners, and averages around 0.25%, which is almost identical to the older model lens.

Autofocus Operation
The Sigma 30mm ƒ/1.4 DC Art is a very good performer in terms of autofocus. The electrical Hyper Sonic Motor focusing system is very fast, accurate and quiet, taking less than a second to move through its full focus range. The HSM system also allows for full-manual focus override, but the lens also has a mechanical manual focus switch on the side of the barrel.

Macro
With a minimum focusing distance just shy of of a foot at 11.8 inches, and a maximum magnification ratio of just 1:6.8, the Sigma 30mm ƒ/1.4 DC Art isn't a great macro performer.

Build Quality and Handling
The Sigma 30mm ƒ/1.4 DC Art is a nice, solid lens with a good heft, but not overly heavy or bulky. By itself, the lens weighs 423.5g (14.9oz), and the lens hood adds another 38.4g (1.4oz). Size-wise, the new lens is 2.5 inches wide, and just shy of 3 inches long. The included lens hood adds about 1.5 inches of additional length. The bayonet-style hood also adds a bit of extra width to the lens.

The barrel is constructed out of Sigma's new Thermally Stable Composite Material, which has been used in other Global Vision lenses such as the Sigma 120-300mm ƒ/2.8 OS Sport lens. The material feels very much like metal and has a smooth, matte black finish. The lens hood, however, has a similar matte black finish, but is made of a sturdy, polycarbonate plastic.

The optical construction has also received an update with 9 elements in 7 groups with one aspherical element. The older model had 7 elements in 7 group with a hybrid aspherical lens and two Special Low Dispersion elements. The aperture diaphragm has also been improved with a new rounded, 9-bladed design over the 8-bladed older model.

The focus ring sits right at the front of the lens and is about half an inch wide, with about 75% being covered with a deeply-ridged rubber grip. The focus ring is very smooth to rotate, but not so loose that a slight brush against it would throw off your focus. There are soft stops for minimum and infinity focus distances, but the ring will still rotate beyond these points. There are also a row of sculpted ridges along the bottom side of the lens's mid-section for an easy grip on the barrel. Other cosmetic features include a focus window with distance markings, as well as a physical switch to toggle AF and manual focus.

Alternatives

Canon EF 35mm ƒ/1.4L USM ~ $1,479
On the Canon side of things, there isn't an exact direct competitor, as Canon doesn't make a 30mm prime lens for APS-C cameras. The Canon 35mm ƒ/1.4L lens has the same fast, ƒ/1.4 aperture with an approximately 56mm FOV on an APS-C camera. Based on our tests, it actually shows similar sharpness to the Sigma on a sub-frame camera, but with better distortion control and slightly improved vignetting performance. The big downside is that it's nearly three times the price.

Canon EF 35mm ƒ/2 IS USM ~ $549
There's also the Canon 35mm ƒ/2 IS, which shows similar sharpness at ƒ/2 and better distortion and CA control on a sub-frame camera, but you miss out on the ƒ/1.4 aperture. However, the included Image Stabilization is a nice bonus for low-light still shooting and video recording. It's also about $100 more expensive than the Sigma, but the Canon can also be used on a full-frame camera.

Canon EF 28mm ƒ/1.8 USM ~ $449
A third option for Canon users is the Canon EF 28mm ƒ/1.8 USM, which has a more similar field of view on a sub-frame camera to the Sigma 30mm lens at approximately 44.8mm. At the wider apertures, such as ƒ/4 and bigger, the Sigma 30mm has better sharpness and shows significantly less CA. The Canon is a tad cheaper however, but doesn't have as wide an aperture.

Nikon 35mm ƒ/1.8G DX ~ $197
In the Nikon camp, there is a fast DX-format prime, the Nikon 35mm ƒ/1.8G DX lens. The Sigma has slightly better image sharpness than the Nikon, as well as better vignetting control. You lose two thirds of a stop with the maximum ƒ/1.8 aperture, but the Nikon more than makes up for the differerence in performance with a much lower price around $200!

Conclusion
Overall, the new Sigma 30mm ƒ/1.4 DC Art is a fantastic APS-C fast prime lens that delivers great image quality with nice, sharp images, low vignetting and only slight barrel distortion. While CA is bit more pronounced versus its predecessor, overall it's a very minor issue.

The cosmetic as well as optical configuration are the biggest changes. The new Global Vision redesign gives this lens a very high quality build, which feels great in the hand. There's now more glass inside the barrel and the improved rounded, 9-blade aperture should make for better bokeh, especially when shooting wide open at ƒ/1.4.

Like other Sigma lenses, price is another big factor to their appeal, and even more so when you factor in their improved build quality nowadays with their Global Vision designs. At around $500, this lens is a very solid performer that won't put a big dent in your wallet. If you're an APS-C shooter in need of a great low-light lens or a serious "bokeh-monster," then the Sigma 30mm ƒ/1.4 DC Art lens should be at the top of your list.

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.